SIST EN 61724-1:2017

Photovoltaic system performance - Part 1: Monitoring

This part of IEC 61724 outlines equipment, methods, and terminology for performance
monitoring and analysis of photovoltaic (PV) systems. It addresses sensors, installation, and
accuracy for monitoring equipment in addition to measured parameter data acquisition and
quality checks, calculated parameters, and performance metrics. In addition, it serves as a
basis for other standards which rely upon the data collected.

Betriebsverhalten von Photovoltaik-Systemen - Teil 1: Überwachung

Performance d'un système photovoltaïque - Partie 1: Surveillance

l’IEC 61724-1:2017 présente des équipements, des méthodes et une terminologie relatifs à la surveillance des performances et à l’analyse des systèmes photovoltaïques (PV). Elle traite des capteurs, des installations et de l’exactitude des équipements de surveillance en plus de l’acquisition des données et des contrôles qualité des paramètres mesurés, des paramètres calculés et des mesures de performances. En outre, elle sert de base à d’autres normes qui s’appuient sur les données collectées.

Zmogljivost fotonapetostnega sistema - 1. del: Spremljanje in nadzorovanje

Ta del standarda IEC 61724 opisuje opremo, metode in terminologijo za spremljanje in nadzorovanje zmogljivosti ter analizo fotonapetostnih (PV) sistemov. Poleg pridobivanja podatkov o izmerjenem parametru in preverjanjih kakovosti, izračunanih parametrov ter metrike zmogljivosti obravnava senzorje, namestitev in natančnost opreme za spremljanje. Poleg tega se uporablja kot osnova za druge standarde, ki se zanašajo na zbrane podatke.

General Information

• Status: Published
• Publication Date: 08-Jun-2017
• ICS: 27.160 - Solar energy engineering
• Technical Committee: PVS - Solar photovoltaic energy systems
• Current Stage: 6060 - National Implementation/Publication (Adopted Project)
• Start Date: 31-May-2017
• Due Date: 05-Aug-2017
• Completion Date: 09-Jun-2017
• Ref Project: EN 61724-1:2017 - Photovoltaic system performance - Part 1: Monitoring

Relations

• Replaced By: SIST EN IEC 61724-1:2021 - Photovoltaic system performance - Part 1: Monitoring
• Effective Date: 01-Nov-2021
• Replaced By: SIST EN IEC 61724-1:2021 - Photovoltaic system performance - Part 1: Monitoring
• Effective Date: 07-Jun-2022
• Replaces: SIST EN 61724:2001 - Photovoltaic system performance monitoring - Guidelines for measurement, data exchange and analysis
• Effective Date: 01-Jul-2017
• Replaces: SIST EN 61724:2001 - Photovoltaic system performance monitoring - Guidelines for measurement, data exchange and analysis
• Effective Date: 07-Jun-2022

Standards Content (Sample)

SLOVENSKI STANDARD
SIST EN 61724-1:2017
01-julij-2017
1DGRPHãþD
SIST EN 61724:2001
Zmogljivost fotonapetostnega sistema - 1. del: Spremljanje in nadzorovanje
Photovoltaic system performance - Part 1: Monitoring
Ta slovenski standard je istoveten z: EN 61724-1:2017
ICS:
27.160 6RQþQDHQHUJLMD Solar energy engineering
SIST EN 61724-1:2017 en
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

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SIST EN 61724-1:2017

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SIST EN 61724-1:2017


EUROPEAN STANDARD EN 61724-1

NORME EUROPÉENNE

EUROPÄISCHE NORM
May 2017
ICS 27.180 Supersedes EN 61724:1998 (partially)
English Version
Photovoltaic system performance - Part 1: Monitoring
(IEC 61724-1:2017)
Performance d'un système photovoltaïque - Partie 1: Betriebsverhalten von Photovoltaik-Systemen - Teil 1:
Surveillance Überwachung
(IEC 61724-1:2017) (IEC 61724-1:2017)
This European Standard was approved by CENELEC on 2017-04-07. CENELEC members are bound to comply with the CEN/CENELEC
Internal Regulations which stipulate the conditions for giving this European Standard the status of a national standard without any alteration.
Up-to-date lists and bibliographical references concerning such national standards may be obtained on application to the CEN-CENELEC
Management Centre or to any CENELEC member.
This European Standard exists in three official versions (English, French, German). A version in any other language made by translation
under the responsibility of a CENELEC member into its own language and notified to the CEN-CENELEC Management Centre has the
same status as the official versions.
CENELEC members are the national electrotechnical committees of Austria, Belgium, Bulgaria, Croatia, Cyprus, the Czech Republic,
Denmark, Estonia, Finland, Former Yugoslav Republic of Macedonia, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia,
Lithuania, Luxembourg, Malta, the Netherlands, Norway, Poland, Portugal, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden,
Switzerland, Turkey and the United Kingdom.



European Committee for Electrotechnical Standardization
Comité Européen de Normalisation Electrotechnique
Europäisches Komitee für Elektrotechnische Normung
CEN-CENELEC Management Centre: Avenue Marnix 17, B-1000 Brussels
© 2017 CENELEC All rights of exploitation in any form and by any means reserved worldwide for CENELEC Members.
 Ref. No. EN 61724-1:2017 E

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SIST EN 61724-1:2017
EN 61724-1:2017
European foreword
The text of document 82/1215/FDIS, future edition 1 of IEC 61724-1, prepared by IEC/TC 82 “Solar
photovoltaic energy systems" was submitted to the IEC-CENELEC parallel vote and approved by
CENELEC as EN 61724-1:2017.

The following dates are fixed:
(dop) 2018-01-07
• latest date by which the document has to be
implemented at national level by
publication of an identical national
standard or by endorsement
• latest date by which the national (dow) 2020-04-07
standards conflicting with the
document have to be withdrawn

This document supersedes EN 61724:1998 (partially).

Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. CENELEC shall not be held responsible for identifying any or all such patent rights.
Endorsement notice
The text of the International Standard IEC 61724-1:2017 was approved by CENELEC as a European
Standard without any modification.
2

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SIST EN 61724-1:2017
EN 61724-1:2017

Annex ZA
(normative)
Normative references to international publications
with their corresponding European publications
The following documents, in whole or in part, are normatively referenced in this document and are
indispensable for its application. For dated references, only the edition cited applies. For undated
references, the latest edition of the referenced document (including any amendments) applies.
NOTE 1 When an International Publication has been modified by common modifications, indicated by (mod), the relevant

EN/HD applies.

NOTE 2 Up-to-date information on the latest versions of the European Standards listed in this annex is available here:
www.cenelec.eu.
Publication Year Title EN/HD Year
IEC 60050-131 -  International Electrotechnical Vocabulary - -
(IEV) -- Part 131: Circuit theory
IEC 60904-2 -  Photovoltaic devices - Part 2: EN 60904-2 -
Requirements for photovoltaic reference
devices
IEC 60904-3 -  Photovoltaic devices - Part 3: EN 60904-3 -
Measurement principles for terrestrial
photovoltaic (PV) solar devices with
reference spectral irradiance data
IEC 60904-5 -  Photovoltaic devices -- Part 5: EN 60904-5 -
Determination of the equivalent cell
temperature (ECT) of photovoltaic (PV)
devices by the open-circuit voltage method
IEC 60904-10 -  Photovoltaic devices -- Part 10: Methods of EN 60904-10 -
linearity measurement
IEC 61557-12 -  Electrical safety in low voltage distribution EN 61557-12 -
systems up to 1 000 V a.c. and 1 500 V
d.c. - Equipment for testing, measuring or
monitoring of protective measures -- Part
12: Performance measuring and
monitoring devices (PMD)
IEC 62053-21 -  Electricity metering equipment (a.c.) - EN 62053-21 -
Particular requirements -- Part 21: Static
meters for active energy (classes 1 and 2)
IEC 62053-22 -  Electricity metering equipment (a.c.) - EN 62053-22 -
Particular requirements -- Part 22: Static
meters for active energy (classes 0,2 S
and 0,5 S)
IEC 62670-3 -  EN 62670-3 -
IEC 62817 2014 Solar trackers for photovoltaic systems - EN 62817 2015
Design qualification
ISO 9060 -  Solar energy; specification and - -
classification of instruments for measuring
hemispherical solar and direct solar
radiation
ISO 9488 -  Solar energy - Vocabulary EN ISO 9488 -
ISO 9846 -  Solar energy -- Calibration of a - -
pyranometer using a pyrheliometer
ISO 9847 -  Solar energy - Calibration of field - -
pyranometers by comparison to a
reference pyranometer
IEC/TS 61836 -  Solar photovoltaic energy systems - CLC/TS 61836 -
Terms, definitions and symbols
ISO/IEC Guide 98-1 -  Uncertainty of measurement – Part 1: - -
Introduction to the expression of
uncertainty in measurement
3

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SIST EN 61724-1:2017
EN 61724-1:2017
ISO/IEC Guide 98-3 -  Uncertainty of measurement -- Part 3: - -
Guide to the expression of uncertainty in
measurement (GUM:1995)
ASTM G 183 -  Standard Practice for Field Use of - -
Pyranometers, Pyrheliometers and UV
Radiometers
WMO No 8 -  Guide to meteorological instruments and - -
methods of observation

4

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SIST EN 61724-1:2017



IEC 61724-1

®


Edition 1.0 2017-03




INTERNATIONAL



STANDARD



















Photovoltaic system performance –

Part 1: Monitoring



























INTERNATIONAL

ELECTROTECHNICAL


COMMISSION





ICS 27.160 ISBN 978-2-8322-3988-9



  Warning! Make sure that you obtained this publication from an authorized distributor.


® Registered trademark of the International Electrotechnical Commission

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SIST EN 61724-1:2017
– 2 – IEC 61724-1:2017 © IEC 2017
CONTENTS
FOREWORD . 5
INTRODUCTION . 7
1 Scope . 9
2 Normative references . 9
3 Terms and definitions . 10
4 Monitoring system classification . 13
5 General . 13
5.1 Measurement uncertainty . 13
5.2 Calibration . 14
5.3 Repeated elements . 14
5.4 Power consumption. 14
5.5 Documentation . 14
5.6 Inspection . 14
6 Data acquisition timing and reporting . 15
6.1 Sampling, recording, and reporting . 15
6.2 Timestamps . 16
7 Measured parameters . 16
7.1 General requirements . 16
7.2 Irradiance . 20
7.2.1 On-site irradiance measurement . 20
7.2.2 Satellite remote sensing of irradiance . 25
7.3 Environmental factors . 26
7.3.1 PV module temperature . 26
7.3.2 Ambient air temperature . 27
7.3.3 Wind speed and direction . 27
7.3.4 Soiling ratio . 28
7.3.5 Rainfall . 30
7.3.6 Snow . 30
7.3.7 Humidity . 30
7.4 Tracker system . 31
7.4.1 Single-axis trackers . 31
7.4.2 Dual-axis trackers for >20x systems . 31
7.5 Electrical measurements . 31
7.6 External system requirements . 32
8 Data processing and quality check . 32
8.1 Daylight hours . 32
8.2 Quality check . 33
8.2.1 Removing invalid readings . 33
8.2.2 Treatment of missing data . 33
9 Calculated parameters . 33
9.1 Overview . 33
9.2 Summations . 34
9.3 Irradiation . 34
9.4 Electrical energy . 35
9.4.1 General . 35
9.4.2 DC output energy . 35

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SIST EN 61724-1:2017
IEC 61724-1:2017 © IEC 2017 – 3 –
9.4.3 AC output energy . 35
9.5 Array power rating . 35
9.5.1 DC power rating. 35
9.5.2 AC power rating . 35
9.6 Yields . 35
9.6.1 General . 35
9.6.2 PV array energy yield . 36
9.6.3 Final system yield . 36
9.6.4 Reference yield . 36
9.7 Yield losses . 36
9.7.1 General . 36
9.7.2 Array capture loss . 36
9.7.3 Balance of systems (BOS) loss . 36
9.8 Efficiencies . 37
9.8.1 Array (DC) efficiency . 37
9.8.2 System (AC) efficiency . 37
9.8.3 BOS efficiency . 37
10 Performance metrics. 37
10.1 Overview . 37
10.2 Summations . 38
10.3 Performance ratios . 38
10.3.1 Performance ratio . 38
10.3.2 Temperature-corrected performance ratios . 39
10.4 Performance indices . 40
11 Data filtering . 41
11.1 Use of available data . 41
11.2 Filtering data to specific conditions . 41
11.3 Reduced inverter, grid, or load availability . 41
Annex A (informative) Sampling interval . 42
A.1 General considerations . 42
A.2 Time constants . 42
A.3 Aliasing error . 42
A.4 Example . 43
Annex B (informative) Module backsheet temperature sensor selection and
attachment . 44
B.1 Objective . 44
B.2 Sensor and material selection . 44
B.2.1 Optimal sensor types . 44
B.2.2 Optimal tapes . 44
B.2.3 Cyanoacrylate adhesives and backsheet integrity . 44
B.3 Sensor attachment method . 45
B.3.1 Permanent versus temporary . 45
B.3.2 Attachment location . 45
B.3.3 Sensor attachment. 45
Annex C (informative) Derate factors . 48
Annex D (normative) Systems with local loads, storage, or auxiliary sources . 49
D.1 System types . 49
D.2 Parameters and formulas . 51

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SIST EN 61724-1:2017
– 4 – IEC 61724-1:2017 © IEC 2017
Bibliography . 57

Figure 1 – Possible elements of PV systems . 7
Figure 2 – Sampling, recording, and reporting. 15
Figure B.1 – Sensor attachment, permanent . 46
Figure B.2 – Sensor attachment, temporary . 46
Figure B.3 – Sensor element wire strain relief . 46
Figure D.1 – Energy flow between possible elements of different PV system types . 49

Table 1 – Monitoring system classifications and suggested applications . 13
Table 2 – Sampling and recording interval requirements . 16
Table 3 – Measured parameters and requirements for each monitoring system class . 18
Table 4 – Relation between system size (AC) and number of sensors for specific
sensors referenced in Table 3 . 20
Table 5 – Sensor choices and requirements for in-plane and global irradiance . 21
Table 6 – Irradiance sensor alignment accuracy . 22
Table 7 – Irradiance sensor maintenance requirements . 23
Table 8 – PV module temperature sensor maintenance requirements . 26
Table 9 – Ambient air temperature sensor maintenance requirements . 27
Table 10 – Wind sensor maintenance requirements . 28
Table 11 – Inverter-level electrical measurement requirements . 32
Table 12 – Plant-level AC electrical output measurement requirements . 32
Table 13 – Calculated parameters . 34
Table 14 – Performance metrics . 38
Table D.1 – Elements of different PV system types . 50
Table D.2 – Parameters and equations for different system types . 51

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SIST EN 61724-1:2017
IEC 61724-1:2017 © IEC 2017 – 5 –
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________

PHOTOVOLTAIC SYSTEM PERFORMANCE –

Part 1: Monitoring

FOREWORD
1) The International Electrotechnical Commission (IEC) is a worldwide organization for standardization comprising
all national electrotechnical committees (IEC National Committees). The object of IEC is to promote
international co-operation on all questions concerning standardization in the electrical and electronic fields. To
this end and in addition to other activities, IEC publishes International Standards, Technical Specifications,
Technical Reports, Publicly Available Specifications (PAS) and Guides (hereafter referred to as “IEC
Publication(s)”). Their preparation is entrusted to technical committees; any IEC National Committee interested
in the subject dealt with may participate in this preparatory work. International, governmental and non-
governmental organizations liaising with the IEC also participate in this preparation. IEC collaborates closely
with the International Organization for Standardization (ISO) in accordance with conditions determined by
agreement between the two organizations.
2) The formal decisions or agreements of IEC on technical matters express, as nearly as possible, an international
consensus of opinion on the relevant subjects since each technical committee has representation from all
interested IEC National Committees.
3) IEC Publications have the form of recommendations for international use and are accepted by IEC National
Committees in that sense. While all reasonable efforts are made to ensure that the technical content of IEC
Publications is accurate, IEC cannot be held responsible for the way in which they are used or for any
misinterpretation by any end user.
4) In order to promote international uniformity, IEC National Committees undertake to apply IEC Publications
transparently to the maximum extent possible in their national and regional publications. Any divergence
between any IEC Publication and the corresponding national or regional publication shall be clearly indicated in
the latter.
5) IEC itself does not provide any attestation of conformity. Independent certification bodies provide conformity
assessment services and, in some areas, access to IEC marks of conformity. IEC is not responsible for any
services carried out by independent certification bodies.
6) All users should ensure that they have the latest edition of this publication.
7) No liability shall attach to IEC or its directors, employees, servants or agents including individual experts and
members of its technical committees and IEC National Committees for any personal injury, property damage or
other damage of any nature whatsoever, whether direct or indirect, or for costs (including legal fees) and
expenses arising out of the publication, use of, or reliance upon, this IEC Publication or any other IEC
Publications.
8) Attention is drawn to the Normative references cited in this publication. Use of the referenced publications is
indispensable for the correct application of this publication.
9) Attention is drawn to the possibility that some of the elements of this IEC Publication may be the subject of
patent rights. IEC shall not be held responsible for identifying any or all such patent rights.
International Standard IEC 61724-1 has been prepared by IEC technical committee 82: Solar
photovoltaic energy systems.
This first edition cancels and replaces the first edition of IEC 61724, published in 1998. This
edition constitutes a technical revision.
This edition (in conjunction with IEC TS 61724-2:2016 and IEC TS 61724-3:2016) includes the
following significant technical changes with respect to IEC 61724:
a) IEC 61724 is now written with multiple parts. This document is IEC 61724-1, addressing
PV system monitoring. IEC TS 61724-2 and IEC TS 61724-3 address performance
analysis based on the monitoring data.
b) Three classes of monitoring systems are defined corresponding to different levels of
accuracy and different intended applications.
c) Required measurements for each class of monitoring system are stated, along with the
required number and accuracy of sensors.

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SIST EN 61724-1:2017
– 6 – IEC 61724-1:2017 © IEC 2017
d) Options for satellite-based irradiance measurement are provided.
e) Soiling measurement is introduced.
f) New performance metrics are introduced, including temperature compensated
performance ratios and others.
g) Numerous recommendations and explanatory notes are included.
The text of this standard is based on the following documents:
FDIS Report on voting
82/1215/FDIS 82/1248/RVD

Full information on the voting for the approval of this International Standard can be found in
the report on voting indicated in the above table.
This document has been drafted in accordance with the ISO/IEC Directives, Part 2.
A list of all parts in the IEC 61724 series, published under the general title Photovoltaic
system performance, can be found on the IEC website.
The committee has decided that the contents of this document will remain unchanged until the
stability date indicated on the IEC website under "http://webstore.iec.ch" in the data related to
the specific document. At this date, the document will be
• reconfirmed,
• withdrawn,
• replaced by a revised edition, or
• amended.
A bilingual version of this publication may be issued at a later date.

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SIST EN 61724-1:2017
IEC 61724-1:2017 © IEC 2017 – 7 –
INTRODUCTION
This International Standard defines classes of photovoltaic (PV) performance monitoring
systems and serves as guidance for various monitoring system choices.
Figure 1 illustrates possible major elements comprising different PV system types. The PV
array may include both fixed axis and tracking systems and both flat plate and concentrator
systems. Module-level electronics, if present, may be a component of the monitoring system.
For simplicity, the main clauses of this document are written for grid-connected systems
without local loads, energy storage, or auxiliary sources, as shown by the bold lines in
Figure 1. Annex D includes details for systems with additional components.
Back up Other RNE
Load(s) Utility
source(s) source(s)
on AC grid line
on AC on AC
I , V P P I , V P I , P
I , P
BUac BUac BUac REac Lac Lac Lac FG FG
TG TG
I , P
TL,dcc TL,dcc
V
G
I , P
AC TB,ac TB,ac
V
Pac
I , V P
Aac,ac Aac,ac Aac,ac
I , P I , P
FPac FPac TPac TPac
PCE-BDI PCE-GCI
I ,
Adc,ac
I , P I , P P
TP TP FP FP Adc,ac
V
Adc,ac
V
Pdc
DC
I , I , I ,
Ldc BUdc Adc,dc
V ,
S
V V V
Ldc BUdc Adc,dc
I , P P
I , P TS TS Adc,dc
P P P FS FS
Ldc BUdc REdc
Back up Other RNE
Load(s) Energy
source(s) source(s)
PV array PV array
on DC storage
on DC on DC
IEC

Key
RNE renewable energy
PCE power conditioning equipment
BDI bi-directional inverter
GCI grid-connected inverter
Bold lines denote simple grid-connected system without local loads, energy storage, or auxiliary sources.
Figure 1 – Possible elements of PV systems
The purposes of a performance monitoring system are diverse and can include the following:
G
i
G
i

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SIST EN 61724-1:2017
– 8 – IEC 61724-1:2017 © IEC 2017
• identification of performance trends in an individual PV system;
• localization of potential faults in a PV system;
• comparison of PV system performance to design expectations and guarantees;
• comparison of PV systems of different configurations; and
• comparison of PV systems at different locations.
These diverse purposes give rise to a diverse set of requirements,
...